Patent GB-1132801-A (GB)
Title: Sewing machines
IPC: D05B69/30
Filed: 1966-08-26
Abstract: 1,132,801. Sewing machines. SINGER CO. 26 Aug., 1966 [1 Sept., 1965], No. 38362/66. Heading D1G. In a sewing machine having stitch-forming means comprising a reciprocable needle bar, a shiftably-supported looptaker, and work-feeding mechanism, a single actuator carried on a rotary shaft is adapted to impart inter-related motion to the stitch-forming means in each direction of rotation of the actuator. As described, the actuator is an eccentric operatively connected to a pair of levers having a phase difference of 90 degrees therebetween on rotation of the eccentric, one lever being operatively connected to the needle bar and looptaker, and the other lever being operatively connected to the work-feeding mechanism, whereby thread loop-seizure always occurs while the needle is raised, irrespective of the direction of rotation of the eccentric. Frames. The frame comprises a baseplate 11 supported at one end by a depending flange 12 and at the other end by two legs (13), and a vertical plate-like bracket 14 having a column portion 15, a horizontal arm portion 16 and a head portion (17). Driving. A shaft 22, journalled in a bush 21 rigid with column portion 15, is rigid at one end with a driving pulley 23 and at its other end with a hand wheel 27. An eccentric 24, journalled on shaft 22, has a radial flange 25 formed with a series of holes 26 concentric with shaft 22. A pin 41, slidable in hand wheel 27, normally engages a hole 26 for coupling eccentric 24 to hand wheel 27. An annular groove 40 in pin 41 is engaged by a finger 39 rigid with a disc 35 pivoted at 38 to a bracket 33 rigid with hand wheel 27. Pressure applied to disc 35 at one side of pivot 38 thereby serves to engage pin 41 with a hole 26, and pressure applied at the other side of pivot 38 serves to withdraw pin 41 from the hole 26 for a bobbin-winding operation. Bobbin winding. A shaft (51), rotatable and axially slidable in column 15, is rigid at one end with a rubber wheel 54 and at the other end with a collar 55 axially-recessed to receive a bobbin. Shaft (51) is spring-biased leftwards to disengage wheel 54 from pulley 23. A shaft 52, slidable in column 15, carries a container 64 for holding the bobbin on collar 55, and is spring-biased rightwards. An arm 57, pivoted on a fixed pin 58, carries at one end a stud engageable with a circumferential groove in shaft (51) for holding wheel 54 engaged with pulley 23 during bobbin winding. The other end of arm 57 carries a finger which overlies the bobbin, for engagement by the fully-wound bobbin, whereby arm 57 is tripped to allow wheel 54 to disengage from pulley 23. A bell crank lever 70, pivoted at 71 to frame 14, has a horizontal arm 72 connected by a link 76 to the needle bar 77, and a vertical arm 73 connected to one end of a lever 112 pivoted at 113 to frame 14, the other end of lever 112 being connected by a link 116 to the looptaker-actuating means as described in Specification 1099590. Work feed. A feed dog 134 is secured by screws 140 to a sheet metal feed arm 142 formed at one end with lugs 143 pivoted to lugs 144 on a feed-advance bar 145 pivoted on fixed trunnion screws 146. One end of a bar 173 is pivoted at 174 to a lug 175 on bar 145. A stud 176, carried intermediately on bar 173, is slidable in an arcuate slot 172 formed concentrically with pivot 174 in a plate 169 spaced from a rigid with a plate 170 pivoted on a fixed pin 168. Plate 170 is connected by a link 166 to a bell crank 162 pivoted on a fixed pin 163. Bell crank 162 is pivoted at 161 to a pitman 160, the other end of which is journalled on an eccentric 24 for oscillating plates 169, 170. The other end of bar 173 is connected by a link 177 to a bar 178 which is clamped to baseplate 11 by a screw 181 carried by a bar 179 slidable on baseplate 11. By varying the position of bar 179, stud 176 may be positioned either concentric with pivot 168 for zero feed, or on one side or the other of pivot 168 for varying the extent of forward or reverse feed respectively. The other end of feed bar 142 is connected by a link 152 to a lug 151 on a feed-lift bar 148 pivoted on fixed trunnion screws 149. A pin 192, rigid with bar 148, has a ball and slot connection with one end of a lever 190 pivoted on a fixed pin 191 and connected at its other end by a link 189 to a pivot pin 188 adjustably carried by a bracket 185 rigid with lever 112. Pin 188 is movable from a position concentric with pivot 113 for imparting zero lift to the feed dog, to adjusted positions transverse of pivot 113 for varying the degree of lift imparted to the feed dog. The axes of eccentric 24 and the pivot 71 lie on a substantially vertical line, while the axes of pivots 161 and 163 lie on a substantially horizontal line, whereby the actions of the needle and feed dog are phased substantially 90 degrees apart, and thread loopseizure always occurs while the needle is raised, irrespective of the direction of rotation of eccentric 24.